Disk Utility Icon

Testing and repairing your startup disk

If you have problems with your startup disk, you can use Disk Utility to test and repair it. To do so, you must start up from another disk, such as your Install Mac OS X disc.

You can test and repair disk permissions on your startup disk without starting up from another disk.

  1. Start up your computer using another disk.

    To use the Install Mac OS X disc, insert the disc and restart your computer holding down the Option key, then select the Install Mac OS X disc and click the arrow.

  2. Open Disk Utility.

    In the Mac OS X Installer, choose Utilities > Open Disk Utility.

  3. Select the startup disk you want to repair in the list of disks and volumes, then click First Aid.
  4. Click the button to verify or repair the disk or disk permissions.

Check the S.M.A.R.T. status of your hard disk at the bottom of the window. If it shows "Verified," the disk has nothing wrong at this time. If you see "About to Fail" in red letters, back up your files on the disk as soon as possible and replace the disk.

See also

repairing disks

Checking the S.M.A.R.T status of your hard disk

Open this for me

Disk Utility